Bits & Bytes: Week 4, II and III (DNS & DHCP) Flashcards
What type of Defined Resource Record is used to direct traffic from one domain name to another?
a CNAME record
This type of Defined Resource Record is used to point a certain domain name at a specific IPv4 IP address
an A Record
A single ___________ is configured for one ___________ but a _____________ can have many ___________
A Record, domain name; domain name, A Record
When a client request receives a server response for one domain name containing multiple IP addresses which it iterates through for each request.
DNS Round Robin
Ex.
Server sends first client: 1st IP, 2nd IP, 3rd IP
Server sends next client: 2nd IP, 3rd IP, 1st IP
Then: 3rd IP, 1st IP, 2nd IP
and loop
What is the logic behind dns round robin?
Traffic to a domain’s IP addresses will be fairly balanced
What’s the difference between an A record and a Quad A Record (AAAA Record)?
A Records are for IPv4, AAAA Records are for IPv6
Which defined resource record type would redirect a server from microsoft.com to www.microsoft.com?
the CNAME resource record
What does CNAME stand for?
Canonical name
ACRONYM:
MX Record
Mail Exchange Record
This resource record is used to deliver e-mail to the correct server
MX records
ACRONYM:
SRV Record
Service Record
This resource record is used to define the location of various specific services
Service Record
Which resource record has a field that’s entirely freeform?
Text Record
Which resource record can be used to communicate data not originally intended to be communicated via DNS?
Text resource records
What are used to demarcate where control moves from a TLD server to a an authoritative server?
Domains
ACRONYM:
FQDN
Fully Qualified Domain Name
How many levels of a domain, in total, can DNS support for a single FQDN?
127 levels
How long can an individual section of a domain name be?
63 characters
What is the maximum number of characters allowed for an entire FDQN?
255 characters
Zone files are simple configuration files that declare what?
Resource Records for a particular DNS zone.
These allow for easier control over multiple levels of a domain.
DNS Zones
ACRONYM:
SOA
Start of Authority
What declares the zone and the name of the name server that is authoritative for it?
the Start of Authority resource declaration
What type of zone files allow DNS resolvers to request an IP and receive the FQDN associated with that IP in the response?
Reverse lookup zone files
ACRONYM:
PTR
Pointer Record
What type of record resolves an IP to a name?
a Pointer record
Which three things are unique to a network and which is unique to a node out of the DNS server, IP Address, Gateway router and Subnet Mask?
The DNS server, Subnet Mask, and Gateway router are usually unique to a network, while the IP address is unique to a node.
ACRONYM:
DHCP
Dynamic Host Configuration Protocol
This is an application layer protocol that automates the configuration process of hosts on a network.
Dynamic Host Configuration Protocol
client devices like desktops or laptops or even mobile phones do not need a ________ IP address.
Client devices don’t need a static IP address
What enables the configuration of a range of IP addresses for use by client devices?
Dynamic Host Configuration Protocol dynamic allocation
What’s the main difference between dynamic and automatic allocation?
Automatic IP allocation will remember a device and try to assign it the same IP if possible when in range. Dynamic allocation doesn’t keep track of devices.
Manually specified pairing of an IP Address with a MAC number/specific device
Fixed Allocation
ACRONYM:
NTP Servers
Network Time Protocol Servers
This type of server is used to keep all computers on a network synchronized in time
Network Time Protocol Servers
On which TCP/IP network layer will you find DHCP?
The application layer
What is the process used by a DHCP configured client to get information about a network’s configuration is what?
DHCP Discovery
What does a client broadcast to a DHCP server when it would like to be assigned an IP address?
a DHCP Discovery Message
A UDP datagram containing a DHCP discovery message always has which two ports as its destination and source?
Destination: Port 67
Source: Port 68
Where would you find the DHCPDISCOVER message?
Encapsulated in a UDP Datagram
The IP datagram containing the UDP DHCPDISCOVER datagram always has which two IP addresses as its destination and source?
Destination: 255.255.255.255
Source: 0.0.0.0
Which port does a DHCP Server listen on for IP address requests from clients?
Port 67
From which port does a client always send a broadcast request for an IP address?
Port 68
What message is sent with a destination port of 68, and source port of 67, a destination broadcast IP of 255.255.255.255 and a its own source IP?
a DHCPOFFER message
What is sent in response to a DHCPOFFER message?
A DHCPREQUEST message
How does a client device know that a DHCP message is meant for it?
The DHCP message has a field containing its MAC address.
What is the client telling the DHCP Server when it sends a DHCPREQUEST message?
The client is saying that it accepts the IP address that the DHCP Server offered.
What is sent in response to a DHCREQUEST message, thereby completing the DHCP discovery process?
a DHCPACK Message
What begins when a client starts using the IP address it was assigned by a DHCP Server?
A DHCP Lease
How long does a DHCP Lease usually last?
A few days or less
